While scams of any kind are not uncommon and they can reach you in many forms, they usually sit under two categories; either a refund due to overpayment or an outstanding balance due to an underpayment.
Usually these are received by text message or by email.
The DVLA advise that they do not send emails or text messages with links to websites asking to confirm personal details or payment information. The best course of action is to contact the DVLA directly with regards to your car tax or visit the GOV.UK website.